Vehicle trim panel with natural fiber layers

ABSTRACT

An improved material for forming vehicle trim panels includes natural fibers formed reinforcing mats. The natural fibers replaced the prior known use of glass fibers. Prior art glass fibers may sometimes cause skin irritation, and the natural fiber eliminates this problem. The fibrous mats are preferably placed on both sides of the central foam layer, and a decorative layer is placed outwardly of one of the fibrous mats. Various naturally occurring fibrous materials such as hemp may be utilized.

BACKGROUND OF THE INVENTION

This invention relates to a vehicle trim panel having a sandwichconstruction including a central foam layer and fiber mats formed ofnatural fibers on opposed sides of the central foam layer.

Sandwich constructions including fibrous mat layers and centralthermoformable foam layers are widely utilized in manufacturing vehicletrim panels such as headliners. The foam layer provides formability andstrength to the overall trim panel. The fibers provide sound insulationand additional strength. These panels are widely utilized and haveproven successful in achieving functional goals for vehicle trim panels.

There are some concerns with this type of panel, however, due to thefibrous materials that have been utilized. The fibrous materials havealmost always been fiberglass layers having small glass fibers embeddedin a plastic binding layer. The fibers are exposed at the edges of thetrim panel, and thus are handled by assemblers or eventual users of thevehicle. The handling of the glass fiber can cause skin irritation, andthus it is desirable to minimize contact between the glass fibers andany users.

In the prior art, covering edges have been proposed. The covering edgesare not fully satisfactory since they are expensive and requireadditional post-manufacturing steps to be applied. Typically, the trimpanels are cut to size from a larger panel, and the edge would then haveto be placed on the final trim panel. Moreover, the covering edges areunsightly.

SUMMARY OF THE INVENTION

The instant invention utilizes natural fibrous materials in the fibermat for a trim panel. In a preferred embodiment, a centralthermoformable foam layer is provided with an outer fiber mat. An outerfabric trim layer is then placed on the mat. Appropriate adhesive layerssecure the several panel layers together. In a most preferredembodiment, a second fibrous mat is placed on an opposed side of thefoam layer. An outer scrim is then placed on the second fiber mat.

In preferred embodiments, the fibrous material may be hemp, or hempderived materials. One most preferred material is abaca, a hempderivative generally available from the Philippines. Other fibrousnatural materials may be utilized, including sisal, flax, or othernatural fibrous material. The natural material causes less skinirritation than the glass fibers, and thus overcomes the problems of theprior art.

In one proposed embodiment of this invention, the fibrous mat isprovided by chopping or shredding the fibrous material into two to fourinch pieces. A power resin binder is then melted on the fibrous materialto secure the fibrous material at its intersecting points. The fibrousmat is then assembled into the trim panel as described above.

In a second type of fibrous mat, a paper-like size is first achieved forthe fibrous material. That is, it is chopped to very fine sizes. Aslurry is then formed with the fibrous material, a liquid and acellulose binder. The binder attaches the fibers at intersecting pointsas in the previous embodiment.

The inventive trim panel thus provides all of the benefits of the fiberlayers in the prior art, while eliminating the undesirable skinirritation and other problems due to the glass fibers.

These and other features of the present invention will be bestunderstood from the following specification and drawings, of which thefollowing is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a trim panel made from the inventive material.

FIG. 2 is a cross-sectional view through the inventive trim panel.

FIG. 3 is an enlarged illustration of one portion of a layer in theinventive trim panel.

FIG. 4 shows a portion of an alternative embodiment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows a vehicle trim panel 20, which may be a vehicle headliner.Although the invention is specifically disclosed with reference to aheadliner, other vehicle trim panels such as door panels, etc. may alsobe formed with the inventive material.

As shown in FIG. 2, the trim panel 20 comprises a decorative fabric orfoam outer layer 22. A natural fiber mat 24 is positioned between thisdecorative layer 22 and a central foam layer 26. A second natural fibermat 28 is placed on an opposed side of foam layer 26, and an outerimpervious scrim 30 is then placed outwardly of the natural fiber mat28. Appropriate adhesives 32, 34 and 36 secure the fibrous mat to thefabric and to the foam layer.

The inventive aspect of this invention are essentially drawn to thenatural fiber mat layers 24 and 28. The other layers may be as known inthe prior art.

In one preferred embodiment, the decorative layer 22 may be a knitfabric with a thin urethane foam laminated to one side. Alternatively, aneedled non-woven fiber may be used. The decorative layer is known inthe art, and as mentioned above, forms no portion of this invention. Thefoam layer 26 may be any thermoformable foam such as a polyester blendor a semi-rigid urethane foam. The scrim layer 30 may be a polyester orrayon non-woven material with some surface treatment to prevent air orliquid transfer. The adhesive layer 32 and 34 are both preferablythermosetting adhesives such as cross-linking urethane or isocyanurate.The adhesive layer 36 may be an adhesive film such as a hot meltpolyolefin or polyamide. All of the layers disclosed to this point areas known in the prior art.

The invention utilizes a natural fiber mat for layers 24 and 26. The matmay be composed of one to four inch pieces of hemp, or hemp derivativessuch as abaca. Alternatively, sisal, flax, or other fibrous naturalmaterials may be used. In the embodiment shown in FIG. 3, the fibers 38are secured at their intersections 40 with a hot melt powder binder ofpolyamide or polyester resin. Thus, the fibers would be chopped or shredinto one to four inch pieces, and made into a mat by depositing thefiber resin on the pieces and then heating the fiber resin to secure thefiber pieces at their intersections. In one preferred embodiment, thelayer would be approximately one half millimeter to one millimeterthick. The layer is preferably 40-100 grams/M², and most preferably80-85 grams/M₂.

This mat was manufactured by Astechnologies (of Jasper, Ga.).

In a second embodiment disclosed in FIG. 4, the layers include muchfiner fibers 42 formed to with a binder 44 which is preferably acelluloustic binder. That is, the binder itself would also be anaturally occurring binder. The binder, finely chopped fibers, andpreferably a liquid such as water are formed into a slurry and the matis then formed to be very thin. The mat is typically on the order of aquarter of a millimeter. This mat preferably has a weight of 40-100grams/M², and most preferably 80-85 grams/M². The cellulostic binder maybe wood pulp.

This mat was manufactured by A. B. Fiberduk (of Ystad, Sweden).

Although specific natural fibers are disclosed for use in the naturalfiber mats, other fibers are within the scope of this invention. Informing the inventive trim panel, the several layers are firstindividually formed. That is, the natural fiber mat is first formed toinclude its fibers and binder. Layers are then assembled in place. Thefinished trim panel 20 is formed by first placing the sandwich of layersinto a heated mold which is preferably at 250°-325°. The sandwich isthen compression molded until the adhesives are all fully reacted. Thispart is then placed into a cooling fixture of the same molded shapeuntil it has cooled to 90°-120°. The part is then trimmed to its finalshape by conventional means and packaged for delivery.

Since only natural fibers are utilized, there are no exposed skinirritating glass fibers once the part has been trimmed. The finishedtrim panel can be varied in strength and acoustic performance based onthe weight of the natural fiber mat reinforcement and the thickness ofthe foam core. The thicker the foam or the higher the weight of thenatural fiber mat used, the stronger the part and the better soundabsorption characteristics will be.

A preferred embodiment of this invention has been disclosed, however, aworker of ordinary skill in the art would recognize that certainmodifications would come within the scope of this invention. Thus, thefollowing claims should be studied to determine the true scope andcontent of this invention.

We claim:
 1. A vehicle headliner comprising:an outer decorative layer;an inner foam core; and a fibrous mat positioned between said decorativelayer and said inner foam core, said fibrous mat being formed to includepieces of a naturally occurring fibrous material said fibrous matincluding a binder to secure said fiber pieces.
 2. A vehicle headlineras recited in claim 1, wherein a second fibrous mat is placed on anopposed side of said foam core from said first fibrous mat.
 3. A vehicleheadliner as recited in claim 2, wherein an outer scrim is placed onsaid second fibrous mat on an opposed face from said foam core.
 4. Avehicle headliner as recited in claim 1, wherein said naturallyoccurring fibrous material is a hemp.
 5. A vehicle headliner as recitedin claim 4, wherein said naturally occurring fibrous material is abaca.6. A vehicle headliner as recited in claim 1, wherein said naturallyoccurring fibrous mat is formed from fiber pieces generally falling in arange of one to four inches in length, and having a fine powder binderincluded to secure said fiber pieces.
 7. A vehicle headliner as recitedin claim 6, wherein said binder is a plastic binder.
 8. A vehicleheadliner as recited in claim 1, wherein said fiber pieces are initiallyformed into a slurry of very small sized pieces along with a binder toform said fibrous mat.
 9. A vehicle headliner as recited in claim 8,wherein said binder is a cellulosic binder.
 10. A trim panelcomprising:an outer decorative fabric layer; a central foam core; andfibrous mats placed on both sides of said foam core, with a firstfibrous mat placed between said foam core and said decorative fabric,and a second fibrous mat placed on an opposed side of said foam layerfrom said first fibrous mat, said fibrous mats being formed of naturallyoccurring fibrous material and a binder.
 11. A trim panel as recited inclaim 10, wherein adhesive layers are placed between said foam core andeach of said first and second fibrous mats.
 12. A trim panel as recitedin claim 10, wherein said trim panel is a vehicle headliner.